Sb-TiO₂/C nanofiber paper as a flexible high-performance anode for lithium-ion and sodium-ion batteries

Titanium dioxide (TiO₂) is regarded as a promising anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its low cost, non-toxicity, high safety, and abundant reserves. However, its practical application is severely limited by poor electrical conductivity, low reversible capacity, and sluggish ion diffusion kinetics. To address these critical issues, we successfully synthesized Sb-TiO₂/C nanofiber paper via electrospinning combined with a subsequent calcination, with the core design feature of constructing a rutile/anatase heterojunction that significantly enhances ion and electron transfer kinetics and provides abundant active sites for Li⁺/Na⁺ storage. When used as a freestanding anode without any binders, conductive additives, or current collectors, it delivers a high and stable specific capacity of ∼291 mA h g^-1 at a current density of 500 mA g^-1 after 500 cycles for LIBs and a stable specific capacity of 162 mA h g^-1 at 500 mA g^-1 after 300 cycles for SIBs, which highlights the critical role of the rutile/anatase heterojunction in optimizing the electrochemical performance of TiO₂-based anodes, establishing the prepared Sb-TiO₂/C nanofiber paper as a promising candidate for flexible LIBs and SIBs. This work provides a feasible and scalable strategy for the practical application of TiO₂-based materials in next-generation flexible energy storage devices.